Uniform spherical particle dispersions are to be produced by emulsion polymerization of styrene and other monomers, using principally emulsifier-free methods with possible addition of ionogenic comonomer, with the aim of obtaining wide ranges of particle diameter and surface charge density. The second electroviscous effect will be studied in these systems as a function of particle concentration, particle size and particle charge. Redispersions in viscous media will be studied to investigate time-dependent thixotropic effects. Particle-particle interactions and the order-disorder transition will be studied by laser Doppler scattering.